The present invention relates to safety razors of the type in which a guard structure is manually adjustable to vary the shaving parameters of the razor. The invention is particularly suitable for safety razors of the type having at least one blade permanently bonded in a replaceable plastic cartridge, or of the disposable type formed at least in-part of plastic.
Safety razors having means for adjusting guard structure with respect to blade cutting edge(s) are well known in the art. For example, U.S. Pat. No. 3,375,578 discloses an adjustable band razor cartridge, U.s. Pat. No. 3,358,368 provides an adjustable double edge razor and U.S. Pat. No. 3,203,093 shows an adjustable single edge razor. Movement of the guard structure acts to vary shaving parameters such as shave or tangent angle, exposure and span. Shave angle is measured between the median plane of a blade and a plane extending from the cutting edge of the blade tangent to the skin-engaging surfaces in front of the blade. Exposure is the distance from the cutting edge to a plane tangent to skin-engaging surfaces disposed in front of and behind the cutting edge. Span is the distance between the cutting edge and the skin-engaging surface in front of the cutting edge.